Specific Aims: Secondary metabolites obtained from plants are a rich source of compounds, with anti-cancer activity. Notable examples include taxol from the Pacific Yew (Taxus brevifolia, Taxaceae), vinblastine (Vinca Rosea, Apocynaceae) and camptothecin from (Camptotheca acuminata, Nyssaceae) (31). We propose to join the expertise of Dr. O'Connel's group, "Medicinal Plants of the Southwest Project" at NMSU in isolation and characterization of native plants form the Southwest region of the United States with anti-cancer screening expertise of Dr. Simon's group at the FHCRC to create a collaborative, multi-disciplinary anti-cancer drug discovery program. The rationale for this collaboration is based on the need to identify new sources of anti- cancer agents and to re-examine sources that were tested in cytotoxicity- based assays using assays for specific anti-cancer activities. Thus the goal of the collaboration is to isolate metabolites from plants found in the Southwest and to test them in cell-based assays for specific anti- cancer activity. Students at NMSU will carry out the isolation, while testing for anti-cancer activity will be carried out at the FHCRC. The specific aims of the pilot project are: 1. Continue to collect and characterize extracts from native Southwestern plants. 2. Screen plant extracts in yeast based anti-cancer agent assays. 3. Screen plant extracts in mammalian cell-based anti-cancer assays. 4. Determine organ specificity, genetic or environmental variability for accumulation of anti-cancer agents.